1. Field of the Invention
The invention relates to a fluid actuation device with compensation for wear, particularly for friction clutch mechanisms of the type having a cylinder in which there are placed a first piston extended by a declutching control rod and a second piston resting against a spring, and in which the space between the pistons is filled with an incompressible fluid.
2. Related Art
Such a device is known from French Patent No. 2,142,363. There, an effort is made to maintain permanent contact between the control rod and the declutching mechanism by allowing an escape of fluid corresponding to the increase of the travel of the first piston resulting from the wear of the friction linings.
Devices of this type should have a rapid response and use only a minimum of energy for control.
A solution known from French Patent No. 2,003,456 consists of inserting a hydraulic connection with a bellows between the declutching pedal and the declutching mechanism, whose fluid line is connected to a fluid tank that can be adjusted so as to maintain a constant volume of oil in the connection, particulary during the wear of the friction linings and when the device is inoperative.
Devices of this type multiply the pressure sources, which increases their hysteresis, and require increased monitoring for good operation.